Class: Franz::Watch

Inherits:
Object
  • Object
show all
Defined in:
lib/franz/watch.rb

Overview

Watch works in tandem with Discover to maintain a list of known files and their status. Events are generated when a file is created, destroyed, or modified (including appended, truncated, and replaced).

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}) ⇒ Watch

Start a new Watch thread in the background.

Parameters:

  • opts (Hash) (defaults to: {}) —

    options for the watch

Options Hash (opts):

  • :input_config (InputConfig) —

    shared Franz configuration

  • :discoveries (Queue) — default: [] —

    “input” queue of discovered paths

  • :deletions (Queue) — default: [] —

    “output” queue of deleted paths

  • :watch_events (Queue) — default: [] —

    “output” queue of file events

  • :watch_interval (Fixnum) — default: 1 —

    seconds between watch rounds

  • :stats (Hash<Path,State>) — default: [] —

    internal “stats” state

  • :logger (Logger) — default: Logger.new(STDOUT) —

    logger to use



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# File 'lib/franz/watch.rb', line 25

def initialize opts={}
  @ic = opts[:input_config] || raise('No input_config specified')

  @discoveries  = opts[:discoveries]  || []
  @deletions    = opts[:deletions]    || []
  @watch_events = opts[:watch_events] || []

  @play_catchup   = opts[:play_catchup?].nil? ? true : opts[:play_catchup?]
  @watch_interval = opts[:watch_interval] || 10
  @stats          = opts[:stats]          || Hash.new
  @logger         = opts[:logger]         || Logger.new(STDOUT)

  @statz = opts[:statz] || Franz::Stats.new
  @statz.create :num_watched

  # Make sure we're up-to-date by rewinding our old stats to our cursors
  if @play_catchup
    log.debug event: 'play catchup'
    stats.keys.each do |path|
      if @ic.type path
        stats[path][:size] = opts[:cursors][path] || 0
      else # we shouldn't be watching this file anymore
        stats.delete path
      end
    end
  end

  @stop = false
  @thread = Thread.new do
    until @stop
      until discoveries.empty?
        @stats[discoveries.shift] = nil
      end

      watch.each do |deleted|
        @stats.delete deleted
        deletions.push deleted
      end

      sleep watch_interval
    end
  end

  log.debug \
    event: 'watch started',
    discoveries: discoveries,
    deletions: deletions,
    watch_events: watch_events,
    watch_interval: watch_interval
end

Instance Method Details

#state ⇒ Object

Return the internal “stats” state



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# File 'lib/franz/watch.rb', line 88

def state
  return @stats.dup
end

#stop ⇒ Hash

Stop the Watch thread. Effectively only once.

Returns:

  • (Hash) —

    internal “stats” state



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# File 'lib/franz/watch.rb', line 79

def stop
  return state if @stop
  @stop = true
  @thread.kill
  log.debug event: 'watch stopped'
  return state
end